Marking pen with excellent cap-off performance

ABSTRACT

A marking pen having an excellent cap-off performance which comprises at least a colorant, a solvent and a resin and, if necessary, an erasability-providing agent as ink components and in which a pen tip comprising a fibrous feed or a plastic feed is coated with a coating agent comprising a substance providing a cap-off property, wherein the above coating agent comprises petroleum waxes comprising hydrocarbons having side chains as a principal component (50% by weight or more). Preferably, the above petroleum waxes comprising hydrocarbons having side chains as a principal component have a melting point of 63° C. or lower and are solid at room temperature.

TECHNICAL FIELD

The present invention relates to a marking pen having an excellentcap-off performance which has a good writing performance even after thepen tip is left standing in the air for a long period of time.

BACKGROUND ART

A marking pen in which an ink is penetrated into a pen tip comprising afibrous feed or a plastic feed so as to be writable has so far been usedin many cases.

However, when a cap of such marking pen is taken away to leave a pen tippart standing in the air for long time, there involved is the problem inthat the pen tip part is dried to cause inferior writing.

In the past, in a marking pen which is excellent in a cap-offperformance of inhibiting drying at the pen tip, higher fatty acidesters of polyglycerin were added to inks (Japanese Patent PublicationS62-34352/1987); paraffin waxes which can be deposited on the surface ofa pen tip to form a thin film were added to inks (Japanese PatentPublication H01-35028/1989); hexaglyceryl tristearate was added to inks(Japanese Patent Application Laid-Open No. H02-232277/1990); andlecithin was added to inks (Japanese Patent No. 2594457).

However, many of additives having a high vaporization-inhibiting effecthas a low solubility (10% by weight or less) in ink solvents and has aproblem in terms of this low solubility. In particular, the solubilityin the vicinity of 0° C. is low (5% by weight or less), whereby thereinvolved are the problems in that precipitations of the additivesdescribed above are produced in the inks while pens are stored at a lowtemperature or exposed repeatedly to low and high temperatures, therebycausing clogging in the ink passages to reduce the writing property ordeteriorate the cap-off property with the passage of time. Thus, theeffective vaporization-inhibiting effect is not yet achieved.

Accordingly, the present inventors have filed a patent application forwriting instruments such as a marking pen, a felt-tip pen and a writingbrush pen having an excellent cap-off performance in which a pen tipcomprising a fibrous feed or a plastic feed is coated with a substanceproviding a cap-off property (PCT Publication No. WO2000/37265).

These writing instruments in which a pen tip comprising a fibrous feedor a plastic feed is coated with a substance providing a cap-offproperty are excellent in a cap-off property but are not yetsatisfactory, and it is the existing situation that writing instrumentshaving a further better cap-off property are required.

Further, in marking pens for a writing board such as markers for a whiteboard among marking pens, those in which pen tips comprising a fibrousfeed or a plastic feed are coated with petroleum waxes such as paraffinwax as a substance providing a cap-off property have had a problem interms of a little bad cap-off property as compared with other markingpens than those for a writing board in which pen tips are coated withpetroleum waxes such as paraffin wax as a substance providing a cap-offproperty.

In light of the problems on the conventional techniques described above,the present invention intends to solve them, and an object thereof is toprovide a marking pen having an excellent cap-off performance whichprovides a good writing performance even after the pen tip is leftstanding in the air over a long period of time.

DISCLOSURE OF THE INVENTION

Intensive investigations of the problems on the conventional techniquesdescribed above have resulted in finding that in a marking pen for awriting board, the cause of providing a low cap-off performance ofpetroleum waxes such as paraffin wax has something to do with asolubility thereof in an erasability-providing agent added as an inkcomponent for the marking pen for a writing board. That is, it has beenfound that petroleum waxes comprising linear hydrocarbons having no sidechains as a principal component among substances providing a cap-offproperty have a large solubility in an erasability-providing agent andtherefore film formation is inhibited by the erasability-providingagent, so that the cap-off performance is deteriorated. On the otherhand, it has been found that petroleum waxes comprising hydrocarbonshaving side chains as a principal component have a small solubility inan erasability-providing agent and therefore the erasability-providingagent exerts a small effect to film formation and that because of a lowcrystallinity thereof, the waxes are uniformly spread when forming acoating film in a marking pen in which a pen tip comprising a fibrousfeed or a plastic feed is coated with a substance providing a cap-offproperty to form the coating film having no gaps, so that obtained is amarking pen meeting the object described above which can achieve a goodcap-off property.

Further, it has been found that also when adding petroleum waxescomprising hydrocarbons having side chains as a principal component asan ink component for a marking pen without coating a pen tip comprisinga fibrous feed or a plastic feed with a coating agent comprising asubstance providing a cap-off property, a coating film having no gapscan be formed on the pen tip without reducing the writing performanceand that a marking pen which can achieve a good cap-off performance isobtained.

That is, the present invention comprises the following items (1) to (7).

-   (1) A marking pen having an excellent cap-off performance which    comprises at least a colorant, a solvent and a resin as ink    components and in which a pen tip comprising a fibrous feed or a    plastic feed is coated with a coating agent comprising a substance    providing a cap-off property, wherein the coating agent described    above comprises petroleum waxes comprising 50% by weight or more of    hydrocarbons having side chains.-   (2) A marking pen having an excellent cap-off performance comprising    at least a colorant, a solvent and a resin as ink components and    having a pen tip comprising a fibrous feed or a plastic feed,    wherein petroleum waxes comprising 50% by weight or more of    hydrocarbons having side chains are involved in the ink components.-   (3) The marking pen having an excellent cap-off performance as    described in the above item (1) or (2), wherein the petroleum waxes    comprising 50% by weight or more of hydrocarbons having side chains    described above have a melting point of 63° C. or lower and are    solid at room temperature.-   (4) A marking pen for a writing board having an excellent cap-off    performance, wherein in the marking pen as described in any of the    above items (1) to (3), an erasability-providing agent is further    involved as the ink component, and the colorant is a pigment.-   (5) The marking pen for a writing board having an excellent cap-off    performance as described in the above item (4), wherein the    erasability-providing agent described above is at least one selected    from substances having an alkyl group having 4 or more carbon atoms.-   (6) The marking pen for a writing board having an excellent cap-off    performance as described in the above item (4) or (5), wherein the    erasability-providing agent has a vapor pressure of 0.1 mm Hg or    less at 20° C.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory drawing showing in a cross sectional mode, oneexample in which the present invention is applied to a free ink typemarking pen.

FIG. 2 is an explanatory drawing showing in a cross sectional mode,another example in which the present invention is applied to a markingpen equipped with a valve mechanism.

FIG. 3 is an explanatory drawing showing in a cross sectional mode, asanother example of the present invention, a marking pen of a type inwhich an ink is occluded in an ink reservoir such as a sliver.

BEST MODE FOR CARRYING OUT THE INVENTION

The embodiments of the present invention shall be explained below indetails.

The marking pen having an excellent cap-off performance in the firstinvention of the present invention is a marking pen which comprises atleast a colorant, a solvent and a resin as ink components and in which apen tip comprising a fibrous feed or a plastic feed is coated with acoating agent comprising a substance providing a cap-off property,wherein the coating agent described above comprises petroleum waxescomprising hydrocarbons having side chains as a principal component.

Also, the marking pen having an excellent cap-off performance in thesecond invention of the present invention is a marking pen comprising atleast a colorant, a solvent and a resin as ink components and having apen tip comprising a fibrous feed or a plastic feed, wherein petroleumwaxes comprising hydrocarbons having side chains as the principalcomponent are involved in the ink components described above.

Further, also included as one embodiment of the present invention is amarking pen for a writing board which comprises an erasability-providingagent as a ink component and in which a pigment is used for the colorantin the first invention and the second invention each described above.

When the “present invention” is hereinafter referred to, it involves thefirst invention and the second invention each described above.

The marking pen in the present invention shall not specifically berestricted as long as it is a marking pen having a pen tip comprising afibrous feed or a plastic feed, and it includes, for example, (1) asshown in FIG. 1, a free ink type marking pen 10 which has an ink tankpart 11 to be a barrel for directly storing an ink and a collectormember 12 for temporarily holding the ink and in which the ink is fedfrom the ink tank part 11 into a pen tip 13 via a feed 14 (or directly),(2) as shown in FIG. 2, a marking pen 20 which has an ink tank part 21to be a barrel for directly storing an ink and in which an ink is fedfrom the ink tank part 21 into a pen tip 22 via a valve mechanism part23 directly (or via a feed) and (3) as shown in FIG. 3, a marking pen 30which has an ink reservoir 32 occluding an ink in a barrel 31 and inwhich the ink is fed from the above ink reservoir 32 into a pen tip 33directly (or via a feed).

In the present invention, a material, a structure and a productionmethod of the pen tip comprising a fibrous feed or a plastic feed shallnot specifically be restricted and include, for example, pen tipscomprising fibrous feeds comprising parallel fiber bundles comprisingone or a combination of two or more kinds of natural fibers, animal hairfibers, polyacetal base resins, acryl base resins, polyester baseresins, polyamide base resins, polyurethane base resins, polyolefin baseresins, polyvinyl base resins, polycarbonate base resins, polyether baseresins and polyphenylene base resins; fiber feeds of felt and the likeprepared by processing fibrous bundles; or fibrous feeds prepared byprocessing fibrous bundles with resins; plastic feeds comprising thevarious plastic materials described above and having grooves for ink inan axial direction; and porous bodies obtained by melting and bondingpowders of the various plastics described above. The forms thereofinclude optional ones such as tabular bodies, fiber-converged bodies,sintered bodies and foamed bodies.

The shape of the pen tip used comprising a fibrous feed or a plasticfeed shall not specifically be restricted as long as it is a shapeusually used for marking pens.

Those having preferably a porosity of 30 to 75% and a slit size, asdefined below, of about 1 to 20 μm are preferred when a fibrous feed isused for the pen tip, and those having an average silt side of 20 to 40μm are preferred when a plastic feed is used for the pen tip.

The porosity and the slit size each described above are varied accordingto the marking pens of the respective types and therefore shall not berestricted to the value ranges described above.

Further, the slit size described above is calculated from the followingequation:slit size=porosity×(radius of yarn)/(1−porosity)

At least a colorant, a solvent, a resin and other additives for amarking pen can be used as the ink components for the marking pen usedin the present invention, and in the case of the marking pen for awriting board, an erasability-providing agent is further used.

The colorant includes oil-soluble dyes and pigments, and a pigment isused particularly for the marking pen for a writing board.

Almost all of conventional oil-soluble dyes which can be dissolved inorganic solvents can be used as the oil-soluble dyes.

The dyes include, for example, Orazol Yellow 2GLN, Orazol Red 3GL,Orazol Blue 2GLN, Neonzapon Blue FLE, Spirit Black SP, Valifast Red1308, Oil Blue BA, Oil Yellow 185, Oil Red TR71, Oil Black S, VictoriaBlue, Rhodamine 6JHSA and Flex Yellow 105, and the pigments shall notspecifically be restricted and include, for example, organic pigmentssuch as azo base pigments, condensed polyazo base pigments,phthalocyanine base pigments, metal complex salt pigments, thioindigopigments, dye lake pigments and fluorescent pigments, and inorganicpigments such as carbon black and titanium oxide. Further, capable ofbeing used as well are processed pigments the surfaces of which areprocessed by coating resins, for example, various Microlys A types, ASBlack, AS Blue and IK Red. These colorants can be used alone or in amixture of two or more kinds thereof. A use amount thereof variesdepending on the kind of the colorant and the other ink components, andit is 1 to 30% by weight, preferably 2 to 15% by weight based on thetotal amount of the ink.

The solvent which can be used in the present invention includes, forexample, lower alcohols such as ethyl alcohol, propyl alcohol andisopropyl alcohol, aromatic hydrocarbons such as toluene and xylene,lower aliphatic ketones such as methyl ethyl ketone and methyl isobutylketone, lower alcohol esters of lower fatty acids such as ethyl acetateand butyl acetate, aliphatic hydrocarbons such as hexane and heptane,alicyclic hydrocarbons such as cyclohexane and ethylcyclohexane andglycol ethers such as propylene glycol monomethyl ether.

These solvents each can be used alone or in a mixture of two or morekinds thereof. A use amount thereof is 50 to 90% by weight, preferably70 to 85% by weight based on the total amount of the ink.

The resin which can be used in the present invention is a resin whichcan be dissolved in a solvent and used as a film-forming agent, asticking agent onto a face to be coated, a viscosity-controlling agentfor the ink and a dispersant for the colorant, and various naturalresins and synthetic resins which have so far been used can be used. Itincludes, for example, rosin base resins such as rosin, ester gums,maleic acid-modified rosin and phenol-modified rosin, cellulose baseresins such as ethyl cellulose and nitrocellulose, vinyl base resinssuch as polyvinylbutyral and vinyl chloride-vinyl acetate copolymerresins, petroleum base resins, ketone base resins, acryl base resins,condensation products of aldehyde and urea and a maleic acid resin. Theycan be used alone or in a mixture of two or more kinds thereof, and ause amount thereof is 0.1 to 30% by weight, preferably 1 to 20% byweight based on the total amount of the ink.

The erasability-providing agent which can be used for the marking penfor a writing board shall not specifically be restricted as long as itis an erasability-providing agent used for a marking pen for a writingboard. It includes preferably at least one (alone or a mixture of two ormore kinds thereof) selected from substances such as alcohols, acids,esters and ethers each having an alkyl group having 4 or more carbonatoms, and they can provide the good erasability.

Used in order to obtain further better erasability is theerasability-providing agent having a vapor pressure of 0.1 mm Hg orless, preferably 0.5 mm Hg or less and more preferably 0.01 mm Hg at 20°C.

The specific substances of alcohols, acids, esters and ethers eachhaving an alkyl group having 4 or more carbon atoms include, forexample, n-octyl alcohol, n-decyl alcohol, lauryl alcohol, myristylalcohol, cetyl alcohol, stearyl alcohol, cetyl octanoate,2-methylpentadecyl octanoate, stearyl octanoate, isostearyl octanoate,2-octyldodecyl 2,2-imethyloctanoate, isostearyl laurate, cetylisooctanoate, 2-methylpentadecyl myristate, propyl myristate, butylpalmitate, 2-methylpentadecyl palmitate, butyl stearate, butylisostearate, isooctyl stearate, dioctyl dodecanedioate, dipropyladipate, dioctyl sebacate, dioctyl azelate, propylene glycolmonostearate, pentaerythritol tetraoctanoate, pentaerythritol tetracaproate, pentaerythritol tetracaprate, pentaerythritol tetracaprylate,pentaerythritol tetralaurate, pentaerythritol tetrastearate,polyoxyethylene alkyl ether phosphoric acid esters, polyoxyethylenealkylphenyl ether phosphoric acid esters, polyoxyethylene alkyl ethersulfuric acid esters, polyoxyethylene alkylphenyl ether sulfuric acidesters, polyoxyethylene alkyl ethers, polyoxyethylene phenyl ether andpolyoxyethylene fatty acid esters. They can be used alone or in amixture of two or more kinds thereof.

A use amount of these erasability-providing agents is 1 to 25% byweight, preferably 2 to 20% by weight and more preferably 5 to 15% byweight based on the total amount of the ink.

If substances (alcohols, acids, esters and ethers) having an alkyl grouphaving less than 4 carbon atoms are used, they are volatilized fromdrawn lines which have been left standing over a long period of time,and the drawn lines can not be clearly erased in a certain case.However, if the erasability-providing agent comprising the substances(alcohols, acids, esters and ethers) having an alkyl group having 4 ormore carbon atoms are used, they are not volatilized even after leftstanding over a long period of time, and the drawn lines can clearlyerased.

The substance providing a pen tip with a cap-off performance which isused in the present invention has to contain petroleum waxes comprisinghydrocarbons having side chains as a principal component.

The petroleum waxes comprising hydrocarbons having side chains as aprincipal component used in the present invention include, for example,waxes comprising as a principal component, hydrocarbons having an alkylgroup, a phenyl group and a cyclo ring as side chains and having amolecular weight of 300 to 700 and 20 to 50 carbon atoms.

In the present invention, the substance providing a pen tip with acap-off performance comprises hydrocarbon having a side chain as aprincipal component, and therefore this hydrocarbon having a side chainhas a content of 50% by weight or more, preferably 70% by weight or morebased on the total amount of the petroleum waxes. If this hydrocarbonhaving a side chain has a content of less than 50% by weight, the effectof providing a cap-off property is low, and the effects of the presentinvention can not be achieved.

The petroleum waxes described above comprising hydrocarbons having sidechains as a principal component are preferably those which have amelting point of 63° C. or lower and are solid at room temperature, morepreferably those which have a melting point of 58° C. or lower andparticularly preferably those which have a melting point of 40 to 53° C.and are solid at room temperature.

The petroleum waxes comprising hydrocarbons having side chains as aprincipal component which have a melting point of 63° C. or lower andare solid at room temperature have further excellent crystallinity forproducing microcrystals and allow the wax to be uniformly spread whenforming a coating film to from the coating film having no gaps, and theparticularly excellent cap-off performance can be achieved.

In the first invention of the present invention, the substance providinga cap-off performance comprises the petroleum waxes described abovecomprising hydrocarbons having side chains as a principal component, anda substance providing a cap-off performance other than the petroleumwaxes having this characteristic may be used (used in combination) aslong as the effects of the present invention are not damaged.

The other usable substances providing a cap-off property include, forexample, one or a mixture of two or more kinds selected from the groupconsisting of glycerin derivatives such as diglycerin monostearate,triglycerin monostearate, pentaglycerin tristearate, hexaglycerintristearate and decaglycerin distearate, alkylphosphoric acid esterssuch as polyoxyethylene stearylphosphate, polyoxyethylenesorbitan fattyacid esters such as polyoxyethylenesorbitan monostearate andpolyoxyethylenesorbitan tristearate, polyoxyethylenesorbit fatty acidesters such as polyoxyethylenesorbit hexastearate, paraffin waxes,microcrystalline waxes, pentaerythritol derivatives such aspentaerythritol monostearate and pentaerythritol distearate, lecithin,saccharose esters, polyolefin waxes and ascorbic acid stearate. Thesesubstances have a content of 50% by weight or less, preferably 0 to 30%by weight based on the total amount of the substance providing a cap-offproperty (coating agent).

In the first invention of the present invention, a method for coatingthe fibrous feed or the plastic feed with the coating agent comprisingthe petroleum waxes having the characteristic described above can becarried out by, for example, dissolving the substance described above ina solvent capable of dissolving it, subjecting the fibrous feed or theplastic feed to dipping treatment in the solution or spraying treatmentwith it and then drying by heating or at room temperature. When thesolubility is extremely low, the substance can be coated by dipping thefeed in the heated solution and cooling it.

The solvents for dissolving the substance (coating agent) providing acap-off performance such as the petroleum waxes having thecharacteristics described above include, for example, alcohols such asmethyl alcohol, ethyl alcohol, n-propyl alcohol and isopropyl alcohol,glycols such as ethylene glycol monomethyl ether, ethylene glycolmonoethyl ether and propylene glycol monomethyl ether, ketones such asacetone and methyl ethyl ketone, esters such as methyl acetate, ethylacetate, butyl acetate, ethylene glycol monomethyl ether acetate andpropylene glycol monoethyl ether acetate, ethers such as dimethyl etherand diethyl ether, hydrocarbons such as hexane, isohexane, heptane andmethylcyclohexane, and chlorinated compounds such as chloroform andmethylene chloride.

An amount of the foregoing substance (coating agent) providing a cap-offperformance coated on the fibrous feed or the plastic feed is 0.01 to20% by weight, preferably 0.1 to 10% by weight and more preferably 0.3to 5% by weight in terms of a weight ratio based on the fibrous feed orthe plastic feed.

If the coating amount is less than 0.01% by weight, the effects broughtabout by coating can not be achieved. On the other hand, if it exceeds20% by weight, the substance having a vaporization-inhibiting functionis coated too much on the fibrous feed or the plastic feed, and thefunctions which have to be exerted primarily by the fibrous feed or theplastic feed are damaged. Thus, the ink is less likely to be dischargedto bring about starving, and therefore neither of the amounts ispreferred.

The other additives for a marking pen include, for example, anionic,nonionic and cationic surfactants, preservatives, fungicides, rustpreventives, lubricants and pH-controlling agents.

In the marking pen of the first invention thus constituted, the fibrousfeed or the plastic feed is coated with the petroleum waxes having thecharacteristic described above, whereby the petroleum waxes canuniformly be spread over the surface part of the fibrous feed or theplastic feed to form a fragile coating film having no gaps and thiscoating film prevents the solvent, which is a volatile componentcontained in the ink, from vaporizing. The above coating film is brokenby writing pressure in writing to allow a pen to write. In addition, thepetroleum waxes described above comprising hydrocarbons having sidechains as a principal component coated on the fibrous feed or theplastic feed of the pen tip is dissolved again in the ink only by arequired amount, though the dissolved amount is a little differentdepending on the coated amount described above, and then a new coatingfilm is formed on the pen tip surface by virtue of interaction with theink solvent when the pen tip is exposed to the air next time. This filmformation→writing→film formation→writing - - - can be repeated manytimes, that is, the coating film is always reproduced at the pen tip andbroken in writing. This effect shall be repeated until the ink filled inthe ink tank part or occluded in the ink reservoir is exhausted.

Next, in the marking pen having an excellent cap-off performance in thesecond invention of the present invention, the petroleum waxescomprising hydrocarbons having side chains having the characteristicdescribed above as a principal component are added to the ink comprisingthe ink components for the marking pen, that is, at least the colorant,the solvent and the resin each described above without coating the pentip comprising the fibrous feed or the plastic feed with the coatingagent comprising the substance providing a cap-off property, whereby theintended cap-off performance is exerted.

The petroleum waxes comprising hydrocarbons having side chains as aprincipal component have a content of 0.03 to 10% by weight, preferably0.05 to 8% by weight and more preferably 0.1 to 5% by weight based onthe total amount of the ink.

If the petroleum waxes have a content of less than 0.01% by weight, theeffects of the present invention can not be achieved. On the other hand,if it exceeds 10% by weight, deposits shall be produced in the ink whilepens are stored at a low temperature or exposed repeatedly to low andhigh temperatures, thereby causing clogging in the ink passage to reducethe writing property or deteriorate the cap-off performance with thepassage of time. Accordingly, neither of the amounts is preferred.

In the marking pen of the second invention of the present invention thusconstituted, the physical properties of the ink shall not be damagedeven if the petroleum waxes having the characteristic described aboveare contained in the ink for the marking pen comprising at least thecolorant, the solvent and the resin and, if necessary, theerasability-providing agent, and the petroleum waxes added to the inkform a fragile coating film having no gaps on the surface part of thefibrous feed or the plastic feed. This coating film prevents thesolvent, which is a volatile component contained in the ink, fromvaporizing. The above coating film is broken by writing pressure inwriting to allow a pen to write on a writing member. In addition, thoughthe film structure is a little different depending on the content of thepetroleum waxes contained in the ink, a new coating film is formed onthe pen tip surface by virtue of interaction with the ink solvent whenthe pen tip is exposed to the air next time, and this filmformation→writing→film formation→writing - - - can be repeated manytimes, that is, the coating film is always reproduced at the pen tip andbroken in writing. This effect shall be repeated until the ink filled inthe ink tank part or occluded in the ink reservoir is exhausted.

It is a matter of course that the marking pen of the present inventionshall not be restricted to the embodiments described above and that itcan be changed to various forms as long as the scope of the presentinvention is not changed.

In the first invention of the present invention, the pen tip is coatedwith the coating agent comprising the petroleum waxes comprisinghydrocarbons having side chains having the characteristic describedabove as a principal component. However, in addition to this coating,the petroleum waxes comprising hydrocarbons having side chains describedabove as a principal component can further be added, as is the case withthe second invention described above, to the ink comprising at least thecolorant, the solvent and the resin each described above together.

A content of the petroleum waxes comprising hydrocarbons having sidechains as a principal component can be lower than the content in thesecond invention described above since the above petroleum waxes arealready coated as well on the pen tip, and it is about 0.01 to 5% byweight based on the total amount of the ink.

EXAMPLES

Next, the present invention shall more specifically be explained indetails with reference to examples and comparative examples, but thepresent invention shall not be restricted to the following examples.

The following pen tip and substances providing a cap-off property wereused in the examples of the present invention and the comparativeexamples.

1. Pen Tip

Used as a pen tip was a pen feed comprising a sliver of an acryl fiberand having a weight of 0.17 g, a length of 33 mm and a diameter of 4.0mm (porosity: 55%).

2. Substances Providing a Cap-off Property (Coating Agent)

Used as the substance providing a cap-off property (coating agent) were(1) petroleum wax (molecular weight: 422) comprising hydrocarbon as aprincipal component having a side chain ratio of 80% (functional groupsof a side chain: methyl, cyclopentyl and phenyl), a melting point of 65°C. and 34 carbon atoms, (2) petroleum wax (molecular weight: 394)comprising hydrocarbon as a principal component having a side chainratio of 70% (functional groups of a side chain: methyl, cyclopentyl andphenyl), a melting point of 62° C. and 32 carbon atoms, (3) petroleumwax (molecular weight: 450) comprising hydrocarbon as a principalcomponent having a side chain ratio of 90% (functional groups of a sidechain: methyl, cyclopentyl and methylcyclohexyl), a melting point of 50°C. and 28 carbon atoms, (4) petroleum wax (molecular weight: 352)comprising hydrocarbon as a principal component having a side chainratio of 5% (functional group of a side chain: methyl), a melting pointof 60° C. and 27 carbon atoms and (5) diglycerin monostearate.

These respective petroleum waxes of (1) to (5) were solid at roomtemperature.

Next, a cap-off performance and a long range erasability of the markingpens prepared in the examples of the present invention and thecomparative examples were evaluated by the following methods.

1. Evaluating Method of the Cap-off Performance

The respective marking pens prepared in the respective examples andcomparative examples were left standing in a room of a temperature of25° C. and a humidity of 65% to evaluate a writing performance at 25° C.according to the following criteria relative to the passage of time in acap-off state with the cap taken off.

Evaluation Criteria:

-   ⊚: writable without starving-   ◯: slightly starving at the beginning of writing-   Δ: starving in the first line-   ΔΔ: starving also in the second line-   X: unwritable    2. Evaluating Method of the Long Range Erasability

The respective marking pens for a writing board prepared in Examples 12to 26 and Comparative examples 6 to 10 were used for writing on a whiteboard at 25° C., and a long range erasability of the drawn lines, thatis, the long range erasability observed after the drawn lines on thewhite board were left standing at a temperature of 25° C. and a humidityof 65% for one month, 2 months and 3 months was evaluated according tothe following criteria.

-   ⊚: clearly erasable-   ◯: erasable-   Δ: traces of the drawn lines remain-   x: inerasable

Examples 1 to 11 and Comparative Examples 1 to 5

The respective inks having the blend compositions (blend unit: % byweight) of I-1 to I-5 shown in the following Table 1 were used as inksfor the marking pens.

In respect to the coating method, the substance providing a cap-offproperty described above (the coating agent) was dissolved in methylenechloride, which was a solvent, to prepare a 3% solution, and the pen tipdescribed above was dipped in the solution and continued to be dipped at50° C. for 2 hours. Then, the pen tip was pulled up and put on amesh-like vessel, and it was dried at 50° C. for a whole day and night(24 hours) to remove the solvent.

An amount of the coating agent adhered on the pen tip was represented bya difference in a weight of the ink reservoir before and after thetreatment and shown by a weight % based on the weight of the pen feedbefore the treatment.

Used were the pen feeds A to E which were subjected to treatments shownoutside the column in the following Table 2 and a (untreated). In thepen feed E, the pen feed was subjected to dipping treatment in a mixtureof the coating agents (1) and (5) described above.

Marking pens of a sliver type shown in FIG. 3 were obtained from theinks (4.5 g) described above and the pen feeds.

The respective marking pens were used to evaluate a cap-off performance,that is, a writing performance relative to the passage of cap-off time.

The results thereof are shown in the following Table 2.

TABLE 1 Ink blend composition Ink blend composition I-1 I-2 I-3 I-4 I-5Ethyl alcohol 75   — 74   74   — n-Propanol — 50 — — 50 i-Propanol 7.5 —7.5 7.5 — Propylene glycol — 34 — — 33 monomethyl ether Laropearl A101*¹— 12 — — 12 Alresat KM400*² 10   — 10   10   — Victoria Blue BSA*³ 2.5 3 2.5 2.5  3 Rhodamine 6JHSA*⁴ 2.5  1 2.5 2.5  1 Flex Yellow 105*⁵ 2.5— 2.5 2.5 — Coating agent (2)*⁶ — — 1   — — Coating agent (3)*⁷ — — —1   — Coating agent (4)*⁸ — — — —  1 *¹Condensation product of aldehydeand urea (manufactured by BASF AG.) *²Maleic acid resin (manufactured byHoechst AG.) *³Dye (manufactured by Zeneca Co., Ltd.) *⁴Dye(manufactured by Zeneca Co., Ltd.) *⁵Dye (manufactured by Zeneca Co.,Ltd.) *⁶Petroleum wax comprising as a principal component hydrocarbonhaving a side chain ratio of 70%, a melting point of 62° C. and 32carbon atoms *⁷Petroleum wax comprising as a principal componenthydrocarbon having a side chain ratio of 90%, a melting point of 50° C.and 28 carbon atoms *⁸Petroleum wax comprising as a principal componenthydrocarbon having a side chain ratio of 5%, a melting point of 60° C.and 27 carbon atoms

TABLE 2 Cap-off performance evaluation results Writing performanceevaluation relative to Pen Ink in passage of cap-off time feed Table 1 1day 3 days 1 week 2 weeks 1 month 1.5 month 2 months Example 1 a I-3 ⊚ ⊚⊚ ⊚ ⊚ ⊚ ◯ Example 2 a I-4 ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ◯ Example 3 A I-1 ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ◯Example 4 A I-2 ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ◯ Example 5 B I-1 ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ Example 6 BI-2 ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ Example 7 C I-1 ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ Example 8 C I-2 ⊚ ⊚ ⊚ ⊚⊚ ⊚ ⊚ Example 9 E I-1 ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ◯ Example 10 E I-2 ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ◯Example 11 A I-4 ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ Comparative a I-1 X X Example 1Comparative a I-2 X X Example 2 Comparative a I-5 ΔΔ X X Example 3Comparative D I-1 ⊚ ⊚ ⊚ ⊚ ⊚ ΔΔ X Example 4 Comparative D I-2 ⊚ ⊚ ⊚ ⊚ ⊚ ⊚X Example 5 Pen feed: A: Coating agent (1), adhered amount of 3% basedon the weight of fibrous feed B: Coating agent (2), adhered amount of 3%based on the weight of fibrous feed C: Coating agent (3), adhered amountof 3% based on the weight of fibrous feed D: Coating agent (4), adheredamount of 3% based on the weight of fibrous feed E: Coating agent (1) +Coating agent (5) adhered amount of 3% based on the weight of fibrousfeed (adhered amount of 2.4% + adhered amount of 0.6%) a: untreated

As apparent from the results shown in Table 1 and Table 2 describedabove, it has been found that the marking pens prepared in Examples 1 to11 falling in the scope of the present invention are excellent in acap-off performance in which a good writing performance is achieved ascompared with those prepared in Comparative Examples 1 to 5 fallingoutside the scope of the present invention even after the pen tips areleft standing in the air over a long period of time.

Individually observing the examples, in Examples 1 and 2, the petroleumwaxes having characteristics meeting the present invention were added tothe inks, and in Examples 3 to 11, the coating agents comprising thepetroleum waxes having the characteristics meeting the present inventionwere coated respectively on the pen tips. In particular, in Examples 9and 10, the coating agents further comprising the other substanceproviding a cap-off property in addition to the petroleum waxes havingthe characteristics meeting the present invention were coated on the pentips; and in Example 11, the petroleum waxes having the characteristicsmeeting the present invention were added to the inks, and the coatingagent comprising the petroleum waxes having the characteristics meetingthe present invention was coated on the pen tip.

In contrast with this, to observe the comparative examples, ComparativeExamples 1 and 2 are the marking pens of conventional embodiments; inComparative Example 3, an untreated pen tip is used, and petroleum waxesin which hydrocarbon having side chains is not a principal component(less than 50% by weight) are contained in the ink; and in ComparativeExamples 4 and 5, the pen tips are coated with the coating agentscomprising petroleum waxes in which hydrocarbon having side chains isnot a principal component (less than 50% by weight).

To totally evaluate these Examples 1 to 11 and Comparative Examples 1 to5, it has been found that the marking pens according to the presentinvention in which the petroleum waxes having the characteristicsmeeting the present invention are added to the inks, the marking pens inwhich the coating agents comprising the petroleum waxes having thecharacteristics meeting the present invention are coated on the pen tipsand the marking pens which are the composite types thereof are thosewhich are excellent in a cap-off performance and in which a good writingperformance is achieved even after the pen tips are left standing in theair over a long period of time as compared with the marking pens whichare of conventional embodiments, the marking pens using the inkscontaining petroleum waxes in which hydrocarbon having, side chains isnot a principal component (less than 50% by weight) and the marking penscoated on the pen tips with the coating agents comprising petroleumwaxes in which hydrocarbon having side chains is not a principalcomponent (less than 50% by weight).

Examples 12 to 26 and Comparative Examples 6 to 10

The respective inks having the blend compositions (blend unit: % byweight) of I-6 to I-14 shown in the following Table 3 were used as inksfor the marking pens.

In respect to the coating method, the substance providing a cap-offproperty described above (the coating agent) was dissolved in methylenechloride, which was a solvent, to prepare a 3% solution, and the pen tipdescribed above was dipped in the solution and continued to be dipped at50° C. for 2 hours. Then, the pen tip was pulled up and put on amesh-like vessel, and it was dried at 50° C. for a whole day and night(24 hours) to remove the solvent.

An amount of the coating agent adhered on the pen tip was represented bya difference in a weight of the ink reservoir before and after thetreatment and shown by a weight % based on the weight of the pen feedbefore the treatment.

Used were the pen feeds A to E which were subjected to treatments shownoutside the column in the following Table 4 and a (untreated). In thepen feed E, the pen feed was subjected to dipping treatment in a mixtureof the coating agents (1) and (5) described above.

Marking pens of a sliver type for a writing board shown in FIG. 3 wereobtained from the inks (4.5 g) described above and the pen feed.

The respective marking pens for a writing board were used to evaluate acap-off performance and a long range erasability.

The results thereof are shown in the following Table 4.

TABLE 3 Ink blend composition Ink I-6 I-7 I-8 I-9 I-10 I-11 I-12 I-13I-14 Ethyl alcohol 72.5 — 72.5 — 72.5 — 71.5 71.5 — n-Propanol — 14.0 —14.0 — 14.0 — — 14.0 i-Propanol  7.5 —  7.5 —  7.5 —  7.5  7.5 —Propylene glycol monomethyl ether — 66.0 — 66.0 — 66.0 — — 65.0Poly(vinyl butyral)  5.0  5.0  5.0  5.0  5.0  5.0  5.0  5.0  5.0 Carbonblack  4.0 —  4.0 —  4.0 —  4.0  4.0 — Phthalocyanine blue —  4.0 —  4.0—  4.0 — —  4.0 Erasability-providing agent (1)*¹ 11.0 11.0 — — — — 11.011.0 11.0 Erasability-providing agent (2)*² — — 11.0 11.0 — — — — —Erasability-providing agent (3)*³ — — — — 11.0 11.0 — — — Coating agent(2)*⁴ — — — — — —  1.0 — — Coating agent (3)*⁵ — — — — — — —  1.0 —Coating agent (4)*⁶ — — — — — — — —  1.0 *¹ Substance (stearyl alcohol)having an alkyl group having 4 or more carbon atoms and a vapor pressure(20° C.) of 0.1 mm Hg or less *²Substance (2-ethyl-1-hexanol) having analkyl group having 4 or more carbon atoms and a vapor pressure (20° C.)of exceeding 0.1 mm Hg *³Substance (ethyl propionate) having an alkylgroup having less than 4 carbon atoms *⁴Petroleum wax comprising as aprincipal component hydrocarbon having a side chain ratio of 70%, amelting point of 62° C. and 32 carbon atoms *⁵Petroleum wax comprisingas a principal component hydrocarbon having a side chain ratio of 90%, amelting point of 50° C. and 28 carbon atoms *⁶Petroleum wax comprisingas a principal component hydrocarbon having a side chain ratio of 5%, amelting point of 60° C. and 27 carbon atoms

TABLE 4 Cap-off performance evaluation results Long range Writingperformance evaluation relative to erasability passage of cap-off timeevaluation Pen Ink in One 3 One 2 One 1.5 2 One 2 feed Table 3 day daysweek weeks month month months month months Example 12 a I-12 ⊚ ⊚ ⊚ ⊚ ◯ ΔΔ ⊚ ⊚ Example 13 a I-13 ⊚ ⊚ ⊚ ⊚ ⊚ ◯ Δ ⊚ ⊚ Example 14 A I-6  ⊚ ⊚ ⊚ ⊚ ⊚ ◯Δ ⊚ ⊚ Example 15 A I-7  ⊚ ⊚ ⊚ ⊚ ⊚ Δ Δ ⊚ ⊚ Example 16 B I-6  ⊚ ⊚ ⊚ ⊚ ⊚ ⊚◯ ⊚ ⊚ Example 17 B I-7  ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ Δ ⊚ ⊚ Example 18 C I-6  ⊚ ⊚ ⊚ ⊚ ⊚ ⊚⊚ ⊚ ⊚ Example 19 C I-7  ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ Example 20 E I-6  ⊚ ⊚ ⊚ ⊚ ⊚ ⊚◯ ⊚ ⊚ Example 21 E I-7  ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ◯ ⊚ ⊚ Example 22 B I-8  ⊚ ⊚ ⊚ ⊚ ⊚ ⊚◯ ⊚ ◯ Example 23 B I-9  ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ Δ ⊚ ◯ Example 24 B I-10 ⊚ ⊚ ⊚ ⊚ ⊚ ⊚◯ ◯ Δ Example 25 B I-11 ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ Δ ◯ Δ Example 26 A I-12 ⊚ ⊚ ⊚ ⊚ ⊚ ⊚⊚ ⊚ ⊚ Comparative a I-6  X X ⊚ ⊚ Example 6 Comparative a I-7  X X ⊚ ⊚Example 7 Comparative a I-14 ΔΔ X X ⊚ ⊚ Example 8 Comparative D I-6  ◯ ΔΔΔ X X ⊚ ⊚ Example 9 Comparative D I-7  ⊚ ◯ Δ ΔΔ X X ⊚ ⊚ Example 10 Penfeed A: Coating agent (1), adhered amount of 3% based on the weight offibrous feed B: Coating agent (2), adhered amount of 3% based on theweight of fibrous feed C: Coating agent (3), adhered amount of 3% basedon the weight of fibrous feed D: Coating agent (4), adhered amount of 3%based on the weight of fibrous feed E: Coating agent (1) + Coating agent(5) adhered amount of 3% based on the weight of fibrous feed (adheredamount of 2.4% + adhered amount of 0.6%) a: untreated

As apparent from the results shown in Table 3 and Table 4 describedabove, it has been found that the marking pens prepared in Examples 12to 26 falling in the scope of the present invention are marking pens fora writing board having an excellent cap-off performance in which a goodwriting performance is achieved as compared with those prepared inComparative Examples 6 to 10 falling outside the scope of the presentinvention even after the pen tips are left standing over a long periodof time and that lines drawn on a white board can clearly be erased evenafter the drawn lines are left standing as they are over a long periodof time.

Individually observing the examples, in Examples 12 and 13, thepetroleum waxes having the characteristics meeting the present inventionwere added to the inks, and in Examples 14 to 25, the coating agentscomprising the petroleum waxes having the characteristics meeting thepresent invention were coated respectively on the pen tips. Inparticular, in Examples 20 and 21, the coating agents further comprisingthe other substance providing a cap-off property in addition to thepetroleum waxes having the characteristics meeting the present inventionwere coated on the pen tips; in Examples 22 and 23, theerasability-providing agents having a vapor pressure of 0.1 mm Hg ormore were used; and in Examples 24 and 25, substances having an alkylgroup having less than 4 carbon atoms were used as theerasability-providing agent. In Example 26, the petroleum waxes havingthe characteristics meeting the present invention were added to the ink,and the coating agent comprising the petroleum waxes having thecharacteristics meeting the present invention was coated on the pen tip.

In contrast with this, to observe the comparative examples, ComparativeExamples 6 and 7 are the marking pens for a writing board ofconventional embodiments; in Comparative Example 8, an untreated pen tipis used, and petroleum waxes in which hydrocarbon having side chains isnot a principal component (less than 50% by weight) are contained in theink; and in Comparative Examples 9 and 10, the pen tips are coated withthe coating agents comprising petroleum waxes in which hydrocarbonhaving side chains is not a principal component (less than 50% byweight).

To totally evaluate these Examples 12 to 26 and Comparative Examples 6to 10, it has been found that the marking pens for a writing boardaccording to the present invention in which the petroleum waxes havingthe characteristics meeting the present invention are added to the inks,the marking pens in which the coating agents comprising the petroleumwaxes having the characteristics meeting the present invention arecoated on the pen tips and the marking pens which are the compositetypes thereof are those which are excellent in a cap-off performance andin which a good writing performance is achieved even after the pen tipsare left standing in the air over a long period of time as compared withthe marking pens which are of conventional embodiments, the marking pensusing the inks containing petroleum waxes in which hydrocarbon havingside chains is not a principal component (less than 50% by weight) andthe marking pens coated on the pen tips with the coating agentscomprising petroleum waxes in which hydrocarbon having side chains isnot a principal component (less than 50% by weight).

It has been found that particularly in Examples 12 to 21, use of atleast one which is selected from substances having an alkyl group having4 or more carbon atoms and which has a vapor pressure of 0.1 mm Hg orless at 20° C. as an erasability-providing agent makes it possible tomore clearly erase lines drawn on a white board even after the drawnlines are left standing as they are over a long period of time.

INDUSTRIAL APPLICABILITY

According to the present invention, provided is a marking pen having anexcellent cap-off performance in which a good writing performance isachieved even after the pen tips are left standing in the air over along period of time, and it can suitably be applied to conventionalmarkers using oil base inks, high-lighters, sign pens, paint markers,writing brush pens and correction pens.

1. A marking pen having an excellent cap-off performance which comprisesat least a colorant, a solvent and a resin as ink components and inwhich a pen tip comprising a fibrous feed or a plastic feed is coatedwith a coating agent comprising a substance providing a cap-offproperty, wherein the coating agent comprises petroleum waxes comprising50% by weight or more of hydrocarbons having side chains.
 2. The markingpen having an excellent cap-off performance as described in claim 1,wherein the petroleum waxes comprising 50% by weight or more ofhydrocarbons having side chains described above have a melting point of63° C. or lower and are solid at room temperature.
 3. A marking pen fora writing board having an excellent cap-off performance, wherein in themarking pen as described in claim 2, an erasability-providing agent isfurther involved as the ink component, and the colorant is a pigment. 4.The marking pen for a writing board having an excellent cap-offperformance as described in claim 3, wherein the erasability-providingagent described above is at least one selected from substances having analkyl group having 4 or more carbon atoms.
 5. The marking pen for awriting board having an excellent cap-off performance as described inclaim 4, wherein the erasability-providing agent has a vapor pressure of0.1 mm Hg or less at 20° C.
 6. The marking pen for a writing boardhaving an excellent cap-off performance as described in claim 3, whereinthe erasability-providing agent has a vapor pressure of 0.1 mm Hg orless at 20° C.
 7. A marking pen for a writing board having an excellentcap-off performance, wherein in the marking pen as described in claim 1,an erasability-providing agent is further involved as the ink component,and the colorant is a pigment.
 8. The marking pen for a writing boardhaving an excellent cap-off performance as described in claim 7, whereinthe erasability-providing agent described above is at least one selectedfrom substances having an alkyl group having 4 or more carbon atoms. 9.The marking pen for a writing board having an excellent cap-offperformance as described in claim 8, wherein the erasability-providingagent has a vapor pressure of 0.1 mm Hg or less at 200° C.
 10. Themarking pen for a writing board having an excellent cap-off performanceas described in claim 7, wherein the erasability-providing agent has avapor pressure of 0.1 mm Hg or less at 200° C.
 11. A marking pen havingan excellent cap-off performance comprising at least a colorant, asolvent and a resin as ink components and having a pen tip comprising afibrous feed or a plastic feed, wherein petroleum waxes comprising 50%by weight or more of hydrocarbons having side chains are involved in theink components.
 12. The marking pen having an excellent cap-offperformance as described in claim 11, wherein the petroleum waxescomprising 50% by weight or more of hydrocarbons having side chainsdescribed above have a melting point of 63° C. or lower and are solid atroom temperature.
 13. A marking pen for a writing board having anexcellent cap-off performance, wherein in the marking pen as describedin claim 12, an erasability-providing agent is further involved as theink component, and the colorant is a pigment.
 14. The marking pen for awriting board having an excellent cap-off performance as described inclaim 13, wherein the erasability-providing agent described above is atleast one selected from substances having an alkyl group having 4 ormore carbon atoms.
 15. The marking pen for a writing board having anexcellent cap-off performance as described in claim 14, wherein theerasability-providing agent has a vapor pressure of 0.1 mm Hg or less at20° C.
 16. The marking pen for a writing board having an excellentcap-off performance as described in claim 13, wherein theerasability-providing agent has a vapor pressure of 0.1 mm Hg or less at20° C.
 17. A marking pen for a writing board having an excellent cap-offperformance, wherein in the marking pen as described in claim 11, anerasability-providing agent is further involved as the ink component,and the colorant is a pigment.
 18. The marking pen for a writing boardhaving an excellent cap-off performance as described in claim 17,wherein the erasability-providing agent described above is at least oneselected from substances having an alkyl group having 4 or more carbonatoms.
 19. The marking pen for a writing board having an excellentcap-off performance as described in claim 18, wherein theerasability-providing agent has a vapor pressure of 0.1 mm Hg or less at20° C.
 20. The marking pen for a writing board having an excellentcap-off performance as described in claim 17, wherein theerasability-providing agent has a vapor pressure of 0.1 mm Hg or less at20° C.